Safe distance of cultural and historical buildings from subway lines

摘要

Construction and operation of subways (metros) closed to historical sites have been one of the main concerns of the world heritage protection bodies such as UNESCO. While metros alleviate condense traffic conditions and boost the tourism industry, the metro induced vibrations might damage cultural and historical structures (CHS). Although there have been various studies into the metros vibration characteristics and the CHS protection methods, there is still a lack of sufficient investigations into the measures by which a safe distance of the CHS to the metro can be derived. In response to this need, a thorough theoretical and experimental investigation was made in this research, aiming at developing a safe distance prediction graphs (SD). For this purpose, a finite element model of the track and the surrounding media was developed. The advantage of the model over the current ones is the consideration of the real (in situ) train loading conditions as an input. The model was validated by comparisons of its results with those of a comprehensive field measurement carried out in this research. New classifications of the CHSs and the track sub-structure form the aspect of metro-induced vibrations were developed in this research. Through parametric analyses of the model, the SD was developed for the first time as a function of metro characteristics, geo-mechanical properties of the media between the metro and the CHS, and the type of CHS. The effectiveness and practicability of the SD in construction of new subway lines were illustrated. It was shown that the SD graphs developed here can be taken as an effective tool for the design of subway lines in historical cities.